Annealing of Defects Produced inn-Type Ge by Electron Irradiation at 30°K

Attention is focused upon a primary radiation defect in $n$-type germanium created by 1.5-MeV electron bombardment at 30°K. This defect anneals in a stage centered near 150°K but is not present when specimens are exposed at 10°K to 0.7-MeV electrons or at 77°K to either 1.0-MeV electrons or ${}_{}{}^{60}{}_{}{}^{}\mathrm{Co} \gamma$ rays. The 150°K stage can be shifted to lower temperatures under the influence of white light and, presumably, ionizing radiation. The characteristics of this defect are similar to those found by Vook and Stein for the so-called irradiation-temperature-independent defects produced by electron bombardment of $n$-type silicon in the temperature range 77-150°K. Therefore, we adopt the same model as they, namely, that the defect responsible for the 150°K annealing stage is a nonreorientable divacancy anchored in a fixed orientation by an interstitial nearby ($I-V_2$ defects). From this experiment it can be concluded that the principal defects introduced by irradiation below 65°K with electrons less than 1 MeV are close pairs which anneal in a stage centered near 65°K, whereas irradiation with electrons of energy greater than 1 MeV introduces $I-V_2$ defects also.